Refrigeration at about ambient temperature is currently achieved by using the compression cycle with halogenated hydrocarbons such as freon (Registered Trademark) gas as the refrigerating medium. Freon gas is compressed and the heat of compression i s conducted to atmosphere thereby causing the gas to condense to a liquid. The liquid freon is then passed to the inside of an insulating chamber where it is allowed to expand and evaporate thereby cooling the chamber. The expanded freon gas then returns to a compressor for the cycle to be repeated.
Problems appear to arise when these known refrigerators wear out since, when they are re-cycled or scrapped, it is believed that the freon type gases are released thereby damaging the ionosphere.
An alternative cycle is available in domestic refrigeration and is known as the ammonia adsorption cycle. However, it is less efficient and often less reliable being dependent on the containment of hydrogen gas.